The invention relates to the fine purification of isophoronediamine (IPDA) using a two-stage column setup comprising a partial condenser.
The production of IPDA by aminating hydrogenation of isophorone nitrile (IPN) is known and has been described numerous times.
In the simplest case (U.S. Pat. No. 3,352,913), IPN is reacted in the presence of hydrogen and of an excess of ammonia over a cobalt catalyst. IPN and ammonia initially react with elimination of water to form isophorone nitrile imine, IPNI, which is subsequently hydrogenated to IPDA.

In addition, processes for producing isophoronediamine are known from CN 104230721A, EP 2649042 A and WO 2012126869A.
In EP 2 649 042A isophoronediamine is produced from isophorone nitrile in a one- or two-stage reaction. Isophorone nitrile is initially iminated with ammonia to afford isophorone nitrile imine. Said isophorone nitrile imine is hydrogenated to afford isophoronediamine in the second step. The purification that follows the reaction is likewise divided into two steps. The low boilers are initially removed in a plurality of distillation columns, said low boilers including hydrogen, inert gases, ammonia and low-boiling impurities (low boiler removal). In a final step the pure isophoronediamine is then obtained via two vacuum distillation columns. The first column in turn serves to remove any remaining relatively low-boiling byproducts. In the second column the isophoronediamine is obtained in pure form as tops and thus separated from the organic residues (high boilers).